I had first invented this simple device when I was but twelve years old and had a penchant for things that go boom. While presently taking a film class, this fond memory had percolated to the surface and I decided to revisit my mischievous childhood and my penchant.
BE ADVISED: This may be the teeniest bit unsafe and could result in some kind of harm to yourself, others, or objects, but mostly likely, you'll only make a mess. In any event: by reading this you relinquish all liability on my part in perpetuity for ever and ever!
Step 1: Gather Ye Stuffbuds While Ye May.
Materials:1) Baking Soda (NOT baking powder you fool!!!)
2) Vinegar (I hear they put this in salads sometimes)
3) Toilet Paper (available in most bathrooms around the world)
4) An EMPTY 35mm film canister (I used fujifilm, hover on the pic to see why)
Step 2: Open Yer Can.
Step 3: Fill 'er Up.
Step 4: Could You Spare a Square?
Step 5: Push It... Push It Good.
What follows is one of the more tricky and critical parts of the lesson. Push your finger in the TP ever so slightly to make a small concave surface below the opening of the canister. Be sure not to puncture the TP.
Step 6: The Icing on the Cake.
I say, you ought to fill your concave pouch just a bit less than level to the surface of the canister. By doing so it is less likely that the TP will rupture in the next step.
Step 7: Replace the Cover.
WARNING: At this point your rocket is primed and ready to fire, the following could occur.
1) The permeable layer (the TP) could rupture from pressure created by too much baking soda or other mechanical failure and inadvertently start the chemical reaction. This will create a great mess. Perhaps even an eye injury. If it seems that this is occurring; simply remove the cover, you'll still have a mess, but no buildup of pressure and thus not much of a hazard.
2) If you knock the bottle over, turn it upside down, or generally create a lot of wishy-washy type movement with the liquid, you may again inadvertently activate the chemical reaction, with results similar to warning #1.
Step 8: Exorcise the Excess.
Step 9: Fin.
Take your little film rocket to an open area, making sure to keep it upright during transport. (I once carried one of these all the way from home, on the bus, and to fourth period).
To launch:1) Set the film canister on the ground in your launch area.
2) Take a few deep breaths.
3) Turn the film container onto its top.
4) RUN AWAY!!!
5) Watch from a safe distance.
I thought of putting a video on here which I made of a launch, but I had a great deal of trouble converting my camera's weird-o format and whatnot. My most recent garage experiment shot the rocket up to 10 feet (3m) at which point it banged into the ceiling with a satisfying hollow pop.
PLEASE BE CAREFUL, you might poke out your eye, or at least make it a bit sore.
How does it all work?I'm glad you asked. Most everyone has seen the simple baking soda + vinegar reaction which produces a nice foamy mess. That reaction is the engine of this rocket. The TP acts as a triggering mechanism by separating the components of the chemical reaction until such time as you turn the bottle over. At which point the chemical reaction starts to produce carbon dioxide. Once the pressure is sufficient so that the seal on the cap is unable to contain it, the thing goes shooting up in the air with a bit of noise and some splashing.